Reversing tool for well pipes



May 30, 1967 c. c. BROWN REVERSING TOOL FOR'WELL PIPES 5 Sheets-Sheet lFiled Dec. 7, 1964 C. C. BROWN REVERSING TOOL FOR WELL PIPI-:s

May 30, 1967 5 Sheets-Sheet. 2

Filed Dec. 7, 1964 ATTOP/Vfy May 30, 1967 c. c. BROWN 3,322,006

REVERSING TOOL FOR WELL PIPES Filed Dec. 7, 1964 5 Sheets-Sheet 5ATTORNEY United States Patent 3,322,006 REVERSING TOOL FOR WELL PIPESCicero C. Brown, Brown Oil Tools, Inc., P.O. Box 19236, Houston, Tex.77024 Filed Dec. 7, 1964, Ser. No. 416,308 6 Claims. (Cl. 81-57) Thisinvention relates to intern-al pipe wrenches and more particularly to-reversing tools for use inside pipe strings for unscrewing ortightening threaded connections between pipe string sections.

In the drilling and operation of wells, such as oil, gas, and waterwells, numerous occasions arise wherein sections of pipe strings in awell bore must be unscrewed or backed-otf from the remainder of the pipestring, as in the retrieving of the free sections of a pipe string stuckin a well, or where it is necessary to tighten a loose threadedconnection. As such pipe strings are normally inaccessible toconventional external wrenches, it is desirable to provide a form ofinternal wrench, commonly called a reversing tool for accomplishing thedesired operations. Such tools are run on an operating pipe string andare designed to be operated by right-hand rotation imparted to theoperating string at the surface, to transmit reverse torque to the pipesections to be unscrewed down in the well.

Conventional reversing tools are relatively complicated and areordinarily operable only to unscrew threaded connections and are notcapable or readily adaptable for tightening threaded connections.

Generally stated, this invention contemplates a reversing toolcomprising ya rotatable mandrel, a pair of longitudinally spaced two-waycam operated, pipe-gripping units disposed in the mandrel in position toengage sections of the same pipe string on opposite sides of a threadedconnection between the sections, and reversing gear means mounted on themandrel between the units and operably connected to the mandrel and bothgripping units to simultfaneously transmit opposed rotational forces tothe respective gripping units in response to clockwise rotation of themandrel, and two-way cam means between the mandrel and pipe-grippingelements operable by said rotational force to cause said grippingelements to apply opposed torsional forces to the respective pipesection.

The present invention has for its primary objects the provision of animproved reversing tool which is of relatively simple and compactconstruction; which is eicient in operation for effecting unscrewing ofthreaded connections in a pipe string; and which, by simple end-for-endreversal, may be employed to tighten such threaded connections.

An important object is the provision of a reversing tool operable inresponse to right-hand rotation of Iau operating string tosimultaneously apply oppositely directed torsional gripping forces Itoadjacent pipe sections connected by a threaded joint or coupling wherebyto unscrew or tighten such threaded joints.

Another object is to provide a reversing tool in which the pipe-grippingunits are constructed and arranged to torsionally grip the pipe, whilepermitting sufcient rel-ative longitudin-al movement of the pipe beinggripped to permit the pipe sections to move apart or toward each otherin the unscrewing or tightening of the connecting threaded coupling.

Other and more speciiic objects and advantages of this invention willbecome more readily apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawing which illustratesa reversing tool in accordance with one useful embodiment of thisinvention.

In the drawing:

FIG. 1 is a view, partly in elevation and partly in section,illustrating the reversing tool inserted in a Well pipe preparatory to-unscrewing adjacent sections thereof;

FIG. 2 is a view similar to FIG. 1 showing the tool parts at separationof the adjacent pipe sections;

FIG. 3 is a view similar to the preceding views showing the tool partsinverted for effecting tightening of a threaded joint;

FIG. 4 is an exploded perspective view of some of the reversing elementsof the tool;

FIGS. 5, 8 and 9 are cross-sectional views taken along lines 5-5, 8-8and 9 9, respectively, of FIG. l; and

FIGS. 6 and 7 are cross-sectional views taken along lines 6-6 and 7 7,respectively, of FIG, 2.

Referring to the drawing, the tool comprises a tubular mandrel,designated generally by the letter M, constructed of coaxial upper andlower sections 10 and 11, respectively, threadedly yconnected at 12. Theupper end of upper section 10 is provided with an internally threadedbox 13 for connection into a pipe string P employed in operating thedevice. Lower section 11 may also have an internally threaded box 14 forconnection, where desired, of other tools, such as a landing nipple,collar or joint locators, and the like. The exterior of the mandrelsections are reduced in diameter to provide -a downwardly facing annularshoulder 15 near the upper end of mandrel section 10, and an upwardlyfacing annular shoulder 16 near the lower end of mandrel section 11.Mounted about the exterior of the mandrel between shoulders 15 and 16yare the pipe gripping and reversing elements of the tool. These includeupper and lower pipe-gripping units, respectively designated generallyby the numerals 17 and 18, inter-connected by a torsional drive andreversing structure, designated generally by the numeral 19.

Upper gripping unit 17 comprises a generally tubular slip cage body 20having an axial bore 21 for reception of mandrel section 10. Theexterior of body 20 is reduced in diameter to provide an annular recess22 which is dened at its lower end by the annular wall 23 having anupwardly projecting annular lip 23a mounted about its outer edge, and atits upper end by the lower end face of collar 24 seated on `the upperend of body 20 below shoulder 15 and porvided with a downwardlyextending annular lip 24a about its outer edge. The upper end of collar24 is counterbored to receive an anti-friction bearing 25 and a retainerring 26 seated against shoulder 15 and surrounding mandrel section 10,these being arranged to permit relative rotation between' the mandreland cage body 20.

Mounted within recess 22 surrounding body 20, is a pair of generallysemi-circular pipe-gripping shoes 27 which are normally urged apartradially by means of relatively light coil springs 28 seated in suitablesockets 29 in the opposed inner ends of the shoes, as best seen in FIG.5, the spacing between the inner ends of the shoes permitting a limitedamount of independent movement of the shoes. The upper and lower edgesof the shoes are provided with oppositely extending upper and lowerflanges 30 and 31, respectively, which are adapted, respectively, toengage lips 24a and 23a, whereby the latter will prevent the shoes frombeing radially expelled from recess 22. Each of the shoes is providedcentrally on its external surface with a longitudinally extendingconvex, generally smooth arcuate surface portion 32 whichhas a circularradius adapted to provide smooth or non-gripping engagement with theinner wall of a surrounding pipe, such as the well casing C. Surfaceportion 32 extends for a relatively short, angular distance about theouter periphery of the shoes. On each side of surface portion 32 theexterior of the shoes is olf-set slightly radially inwardly Vat 33 andthese radially oit-set portions are provided with a plurality ofparallel longitudinally extending, radially projecting teeth 34 whichare normally out of contact with casing C when portion 32 is engagedwith the casing wall. The teeth 34 Iare adapted, upon relative rotationbetween the shoes and casing C, to engage the casing and prevent furtherrelative rotation between the shoes and casing, and to then apply astrong torsional force to the casing in response to rotational forcetransmitted from the cage body to the shoes. By reason of thelongitudinal form of the teeth, some longitudinal slippage between theteeth and casing can occur, even though the torsional forces willprevent relative rotation between the teeth and the casing, as willappear subsequently.

To effect the relative rotation or rocking movement of the shoes, theexterior of body 20 within recess 22 is machined to provide a pluralityof oppositely radially extending, longitudinally spaced lugs 35, eachset of lugs on opposite sides of body 20 having registering openings 36through which a cylindrical shaft 37 extends, the ends of the shaftbeing engaged by wall 23 and end face 24 to retain it in the lugs whenthe structure is assembled. A series of rollers 38 are mounted on shaft37 between the several lugs 35 and constitute cam followers, the sets ofthe cam followers thus being mounted on diametrically opposite sides ofbody 20. The inner peripheries of shoes 27 on each side of the centralportion thereof are provided with non-circular cam surfaces 39 which areengageable by cam followers 38 in response to relative rotation betweenthe cage body 20 and the shoes. As best seen in FIG. 6, cam surfaces 39are shown engaged with cooperating cams 38 to rock shoes 27 angularlyrelative to casing C, so as to project teeth 34 into torsional grippingengagement with the wall of casing C.

Lower gripping unit 18 is substantially identical in construction toupper gripping unit 17, except that the unit is inverted, in that collar24 is at the lower end of the unit and is seated against shoulder 16,all of the parts heretofore described in connection with gripping unit17 finding their identical counterparts in gripping unit 18.

The drive and reversing structure, designated generally by the numeral19, includes a series of planetary gear elements which are arranged totransmit the desiredrtorsional forces to the gripping units. These gearelements comprise Y a drive gear formed by gear teeth which, asillustrated, are eut longitudinally in the exterior of mandrel section10, but which, it Will be evident, may be provided by shrinking a ringgear on the exterior of the mandrel or by fabricating in any otherconventional manner. Gear 45 drives through a set of planetary idlergears 46 journalled Vin a spider 52 and arranged'between upper and lowergripping units 17 and 1S, in a manner to be subsequently described.Idler gears 46 mesh with an external gear 47 mounted inside a tubularshell defining upwardly and downwardly extending annular end sections 48and 49, respectively, which extend about the opposed ends of upper andlower bodies 20 of the gripping units. Upward extension 48 isprovidedwith a plurality of longitudinal splines 50 receivable in spline grooves51 formed on the outer face of upper body 20 to form a drive connectionbetween the external gear and upper body 20. By means of this splineconnection, in conjunction with the gear connections previouslydescribed, it will be seen that when mandrel M is rotated in theright-hand or clockwise direction, idler gears 46 will rotate in thecounter-clockwise direction and they, in turn, will drive external gear47 in the counter-clockwise direction, as indicated by the arrows inFIG. 9. Lower end section 49 of the external gear is free to rotateabout body 20 of the lower gripping unit.

YTo support the idler gears 46 in operative relation between drive gear45 and external gear 47, lower body 20 is provided with an elongateextension forming spider 52 which extends upwardly toward the lower endof upper body 20 and is provided with a plurality of angularly spacedslots 53 (FIG. 4) extending downwardly from the upper end of the spiderand defining at their lower ends the bottom walls 54 having cylindricalsockets 55 bored therein. Idler gears 46 are provided with upper andlower cylindrical axles or necks 56 and 57, respectively. Lower necks 57are received in sockets 55 and are journalled in roller bearings 58seated in sockets 55. A collar 60 is mounted on the upper end of spider'52 and is secured thereto by stud-bolts 61 countersunk in the upper endof the collar and screwed into the upper end of spider 52 between slots53. Collar 60 is provided with cylindrical sockets 62 registering withsockets Y55 and adapted to receive upper necks 56 of the idler gears,the necks being journalled in rollerV bearings 63 seated in sockets 62.The upper end of collar 60 is provided on its inner edge with anupwardly extending annular ange 64 spaced from, and concentric with, adownwardly extending tool mounted on pipe P is'run into a well and posi-Y tioned so that the upper and lower gripping units are disposedrespectively above and below a threaded coupling or joint I betweenupper and lower sections C1 and C2, respectively, -of casing C. Thesmooth surfaced mid-sections 32 of the gripping shoes will ride with aslight amount of friction on the inner wall of casing C and as operatingpipe P is rotated in the right-hand or clockwise direction, thismovement will be transmitted through gears 45, 46 and spider 52 to shoes27 of the lower gripping unit, whichr will be rocked thereby in the samedirection, as best seen in FIG. 7, so as to cause teeth 34 to bite intothe wall of casing section C2 below coupling I. Since this section ofthe casing will normally be fixed in the well, further rotation of lowergripping unit 18 will be effectively stopped. At'the same time, the gearconnection between main gear 45, idler gears 46 and external gear 47will necessarily drive the latter in the counter-clockwise direction.Stoppage of rotation of lower gripping unit 18 will then cause externalgear 47, acting through the spline connection formed between splinemembers 56 and 51, to drive body 20 of the upper gripping unit in thecounter-clockwise direction,V las indicated lby the arrows on FIG. 9.This counter-clockwise movement of body 20 of the upper gripping unitwill cause shoes 27 of the latter to be rockedin the counter-clockwisedirection, as illustrated in FIG. 6, and will thereby apply acounter-clockwise torsional force to the upper casing portion C1 abovecoupling I. As this upper casing lportion C1 will be free to rotate, thecontinued clockwise rotation of pipe P will thus be transmitted to theupper gripping unit'and will produce continued counter-clockwiserotation of upper casing C1, while opposed torsional force is applied tolower casing section C2 until upper casingl section C1 will have beencompletely unscrewed from the coupling, las illustrated in FIG. 2. By

the employment of the longitudinally extending form of central positionsin the respective bodies, and thereby release the tool so that it maybe-withdrawn from the wellY or run down to span another lower couplingwhich is to be unscrewed.

In the circumstances where there may be found a threaded coupling orjoint J1 as illustrated in FIG. 3, which it is desired to tighten, thereversing tool previously described is simply turned end-for-end withlower mandrel section 11 coupled to operating pipe P (FIG. 3). The toolis then run into the well to place the now reversed upper and lowergripping units on opposite sides of joint J1. Thereupon, right-hand orclockwise rotation of pipe P will produce the opposed rotations of thegripping units, that is, shoes 27 of gripping unit 18, which is now theupper gripping unit, will be rocked in a direction to apply righthandgripping torque to upper casing section C1, while opposite torsionalforce will be transmitted through reversing section 19 to gripping unit17, which is now the lower gripping unit, causing the latter to applyleft-hand or counter-clockwise torque to lower casing section C2.Gripping unit 18 will now serve as the back-up anchor, while clockwiserotation is transmitted directly from the mandrel to now lower grippingunit 17, thereby rotating lower casing section C2 in thecounter-clockwise direction until joint J1 becomes fully made up. Asonly one or two turns ordinarily will be required in such cases, theseturns and the small corresponding upward movement of lower casingsection C2 may usually be l'attained in the lower casing section eventhough the latter may be secured at some lower point in the well.

It will be understood that various changes and modications may be madein the details of the illustrative embodiment within the scope of theappended claims but without departing from the spirit of this invention.

What I claim and desire to secure lby Letters Patent is:

1. A wrench insertable in a pipe string for unscrewing or tighteningthreaded connections between adjacent sections of the pipe string,comprising,

(a) a mandrel,

(b) means carried by the mandrel for connecting the same to a source oftorsional force,

(c) longitudinally spaced substantially identical pipegripping unitsdisposed on the mandrel in position to engage sections of a pipe stringon opposite sides of a threaded connection between said sections,

(d) each of said units including pipe gripping elements operable inresponse to a rotational force to torsionally grip said pipe sections,and

(e) reversing gear means mounted on the mandrel between the units andoperably connected to the mandrel and both gripping units,

(f) said gear means being constructed and arranged to be operable byrotation of said mandrel in the clockwise direction to simultaneouslytransmit opposed rotational forces to the respective gripping units. M

2. A wrench insertable in la pipe string for unscrewing threadedconnections between adjacent sections of the pipe string, comprising,

(a) a mandrel,

(b) means carried -by the upper end of the mandrel for connecting thesame to a source of rotational force,

(c) longitudinally spaced substantially identical upper and lowerpipe-grippin g units disposed on the mandrel in position to engagesections of a pipe string on opposite sides of a threaded connectionbetween said sections,

(d) each of said units including pipe-gripping elements movably disposedabout said mandrel and cooperating two-way cam means arranged betweensaid mandrel and said pipe-gripping elements operable in response torotational force transmitted from said mandrel to cause saidpipe-gripping elements to exert torsional force on said pipe sections,

(e) reversing gear means mounted on the mandrel between the units andoperably connected to the mandrel and both gripping units,

(f) said gear means being constructed and arranged to be operable byrotation of said mandrel in the clockwise direction to simultaneouslytransmit clockwise rotation-al force to the lower gripping unit andcounter-clockwise rotational force to the upper gripping unit whereby toexert opposed torsional forces by the respective units on the relatedpipe sections to unscrew the threaded connection.

3. A reversing tool insertable in a pipe string 4for unscrewing ortightening threaded connections between adjacent sections of the pipestring, comprising,

(a) mandrel,

(b) means carried by the mandrel for connecting the same to a source ofrotational force,

(c) longitudinally spaced substantially identical pipegripping unitsdisposed about the mandrel in positions to engage sections of a pipestring on opposite sides of a threaded connection between said sections,

(d) each of said units including a body, cooperating pipe-grippingelements positioned about the body and co-operating two-way cam meanscarried by said body and said pipe-gripping elements operable inresponse to relative rotation between the body and said elements tocause said pipe-gripping elements to exert torsional gripping forces onsaid pipe sections, and

(e) reversing gear means mounted about the mandrel between the units andoperably connected to the mandrel and said bodies of both grippingunits,

(f) said gear means being constructed and `arranged to be operable byrotation of said mandrel in the clockwise direction to simultaneouslytransmit oppositely directed rotational forces to said bodies of therespective gripping units, whereby to cause said gripping elements toexert opposed torsional forces on the respective pipe sections.

4. A reversing tool according to claim 3, wherein said reversing gearmeans includes a drive gear mounted about the mandrel, an external gearconcentrically disposed for rotation about said drive gear, a spidersecured to said body of one of said units and carrying a plurality ofplanetary gears drivingly connecting said drive gear to said externalgear, and means forming a drive connection between said external gearand said body of the other one of said units.

5. A reversing tool insertable in a pipe string for unscrewing threadedconnections between adjacent sections of the pipe string, comprising,

(a) mandrel,

(b) means carried by the upper end of the mandrel for connecting thesame to a source of rotational force,

(c) longitudinally spaced substantially identical upper and lower'pipe-gripping units disposed about the mandrel in positions to engagesections of a pipe string on opposite sides of a threaded connectionbetween said sections,

(d) each of said units including a body, cooperating pipe-grippingelements positioned about the body and co-operating two-way cam meanscarried by saidv body and said pipe-gripping elements operable inresponse to relative rotation between the body -and said elements tocause said pipe-gripping elements to exert torsional gripping forces onsaid pipe sections, and

(e) reversing gear means mounted about the mandrel between the units andoperably connected to the mandrel and said bodies of both grippingunits,

(f) said gear means being constructed and arranged to be operable byrotation of said mandrel in the clockwise direction t-o simultaneouslytransmit clockwise rotational force to the body of the lower grippingunit and counter-clockwise rotation to the body of said upper grippingunit whereby to cause said gripping elements to exert opposed torsionalforces on the respective pipe sections in directions to cause unscrewingof said threaded connection.

6. A reversing tool yaccording to claim 5 wherein said reversing gearmeans includes a main drive gear mounted about the mandrel, an externalgear concentrically disposed for rotation about said drive gear, aspider secured to the body of said lower gripping unit and carrying Iaplurality of planetary gears drivingly connecting said drive gear tosaid external gear, and means forming a drive con- 7 nection betweensaid external gear and the body of said 1,627,842 upper gripping unit.1,887,009 2,462,478 References Cited 2,800,043 UNITED STATESV PATENTS 5219471521 1,110,639 9/1914 Moore 166-117.7 1,617,303 2/1927 Dougherty166-117.7

8 Edwards 166'.117.7 Buttress 81-72 Edwards 166-117.7 Young 81-72Tappmeyer 166 -117.7

JAMES L. JONES, JR., Primary Examiner.

1. A WRENCH INSERTABLE IN A PIPE STRING FOR UNSCREWING OR TIGHTENINGTHREADED CONNECTIONS BETWEEN ADJACENT SECTIONS OF THE PIPE STRING,COMPRISING, (A) A MANDREL, (B) MEANS CARRIED BY THE MANDREL FORCONNECTING THE SAME TO A SOURCE OF TORSIONAL FORCE, (C) LONGITUDINALLYSPACED SUBSTANTIALLY IDENTICAL PIPEGRIPPING UNITS DISPOSED ON THEMANDREL IN POSITION TO ENGAGE SECTIONS OF A PIPE STRING ON OPPOSITESIDES OF A THREADED CONNECTION BETWEEN SAID SECTIONS, (D) EACH OF SAIDUNITS INCLUDING PIPE GRIPPING ELEMENTS OPERABLE IN RESPONSE TO AROTATIONAL FORCE TO TORSIONALLY GRIP SAID PIPE SECTIONS, AND (E)REVERSING GEAR MEANS MOUNTED ON THE MANDREL BETWEEN THE UNITS ANDOPERABLY CONNECTED TO THE MANDREL AND BOTH GRIPPING UNITS, (F) SAID GEARMEANS BEING CONSTRUCTED AND ARRANGED TO BE OPERABLE ROTATION OF SAIDMANDREL IN THE CLOCKWISE DIRECTION TO SIMULTANEOUSLY TRANSMIT OPPOSEDROTATIONAL FORCES TO THE RESPECTIVE GRIPPING UNITS.